The invention pertains to a method for optimizing the transmission of signals, especially video signals, over a channel with a predetermined channel data rate after a source encoding for data reduction and a channel encoding, according to which method redundancy is added to the source-encoded signals for error control protection.
Because of the limited resources for the transmission of information (video, audio, data) in existing and future networks, additional measures are taken to maximize the system capacity with respect to number of users, types of service, and applications.
A considerable degree of data reduction is achieved by means of parametric source encoding methods such as MPEG1, MPEG2, and MUSICAM. Here the encoded signal is composed of various sets of parameters with different information contents. As a result, however, there is usually a selective sensitivity of the encoded signals to transmission errors. So-called hierarchical video encoding methods are characterized by an encoded sequence, which is composed of several partial sequences; these partial sequences originate from corresponding encoding processes with different degrees of resolution, and they therefore also have different sensitivities to error. It can be assumed that future object-oriented source encoding methods such as MPEG4 will also be characterized by the nonuniform error sensitivity of their various objects and/or partial objects.